This invention relates generally to golf putters and more particularly concerns a golf putter head which provides a high rotational moment of inertia, a properly aligned center of mass, a reinforcing rearwardly extending flange, and a flat milled striking face, all of which combine to produce a putter having a high degree of accuracy.
In order to putt a golf ball accurately, it is necessary to align the length of the putter face perpendicular to the intended line of the putt, and then keep the length of the putter face perpendicular to that intended line when the ball is contacted during the putting stroke. In addition, accuracy as to distance depends on the amount of energy transferred from the putter head to the ball and how much of that energy is lost to vibration or extraneous torques imparted either to the ball or the club at the moment of impact.
With regard to initial alignment of the putter face, there have been a number of putters proposed which provide aligning indices on the putter which will assist the golfer in aligning the length of the putter blade perpendicular to the intended line of the putt. See, for example, Rozmus U.S. Pat. No. 3,966,210 with its groove along axis 5; Winter U.S. Pat. No. 3,921,986 with its rearwardly extending perpendicular flange 17; Becker U.S. Pat. No. De. 240,445; Antonius U.S. Pat. No. 4,136,877; and Antonius U.S. Pat. No. 4,458,900.
In order to maintain alignment of the length of the putter face perpendicular to the intended line of the putt, the prior art has also disclosed a number of golf putters which have increased rotational moments of inertia to offset the putter's tendency to twist if the ball is struck off of the center of mass of the putter head, either toward the heel or toward the toe of the putter head. Typically, as shown in Duclos U.S. Pat. No. 4,508,350, lead weight inserts are provided in the heel and toe of a standard size putter head cast from aluminum in order to increase the putter head's rotational moment of inertia. Duclos' putter head with its lead weights has a rotational moment of inertia of 4500 gm. cm..sup.2 about the center of mass of the putter head having a conventional static weight of 310 gms. Likewise, weighted putter heads having increased moments of inertia are disclosed in Taylor U.S. Pat. No. 4,325,553; Reiss U.S. Pat. No. 4,444,395; Winter U.S. Pat. No. 3,921,984; Judice U.S. Pat. 3,967,826; Strop U.S. Pat. No. 4,147,357; Cook U.S. Pat. No. 3,931,975; and Long U.S. Pat. No. De. 248,783.
In addition to weighted inserts in the heel and the toe of a putter head, the prior art also discloses weights in the putter head displaced rearwardly of the putter shaft. As the putter is swung forward, the inertia of the weights in the trailing outboard edges of the putter head tends to cause the club head to rotate such that the length of the face of the putter will be perpendicular to the intended line of the putt prior to striking the ball. Such putter heads with weighted trailing edges are disclosed in Rozmus U.S. Pat. No. 3,966,210 and Long U.S. Pat. No. 4,010,958.
In order to assure that the ball, when struck by the putter, travels as far as intended, it is important that the center of mass of the putter head and the center of the mass of the ball lie on a line parallel to the putting surface and aligned with the intended line of the putt. Such an alignment assures the maximum transfer of energy from the putter head to the ball and assures that energy is not wasted by imparting torsional forces to the ball which do not contribute to its linear velocity or by transmitting torsional forces to the putter head which are dissipated by the damping affects of the putter head, the shaft, and the golfer's grip. In addition, energy is transferred from the putter head to the golf ball by providing a putter head which is relatively free of vibration thereby producing a "solid feel" when the putt is struck.
Finally, accuracy in putting is further assured by having the striking face of the putter head as flat as possible. In general, standard putter heads are manufactured by casting which provides a striking face which may vary as much as 0.006 inch in overall smoothness.